| BellSouth | |
|---|---|
| Domains | bellsouth.net |
| Mail routing | mx-att.mail.am0.yahoodns.net in September 2026, which is Yahoo infrastructure reached through AT&T's outsourcing arrangement. |
| What we can resolve | We resolve few mailboxes here |
How BellSouth answers a probe
What the server does when we open a connection and ask about one address.
- Every RCPT TO returns positive, following Yahoo's anti-harvesting policy.
- The catch-all probe also returns 250, so the domain classifies as accept-all.
- Real failures surface as asynchronous bounces hours after a send.
- Nothing about the AT&T or BellSouth brand changes the Yahoo behavior underneath.
The part that catches people out
What we do about it
We label it catch_all, and the mx_host shows Yahoo's servers. That label is a result, so it costs a credit, and what it buys you is the knowledge that no verifier's "valid" on this domain is a measurement. When the server won't answer at all the result is unknown, and unknowns are never billed. On a southeastern US consumer list this domain plus att.net can be a meaningful share of the unresolved total, and knowing why helps more than a number would.
Sending to BellSouth mailboxes
Verification is one step. These are the things that decide whether the message lands.
- Yahoo's bulk sender requirements apply, since Yahoo receives the mail.
- Yahoo's feedback loop is the only complaint signal available for this domain.
- A list with many bellsouth.net addresses is regional and old, which is useful to know before blaming the creative.
A Georgia list, mailed in slices
Say a family-owned pest control company near Atlanta has 4,000 customer emails going back to 2003, and 520 of them are on bellsouth.net. Those 520 come back catch-all, because the Yahoo-run host answers yes to every recipient. The company hasn't emailed anyone in three years and wants to start a quarterly reminder.
Here's a plan that fits a list like that. Send the first reminder to everyone else as normal. Split the 520 into four groups of 130 and mail one group per day. Hard bounces from this system come back after the send, often within hours, sometimes the next day. Each morning, remove the previous day's bounces and look at the rate. If the first slice loses 40 addresses, you know roughly what the other three will do, and you've kept each day's damage small enough that it doesn't color how receivers treat the company's whole send.
The From address on the invoice
Small businesses in the old BellSouth states often still use a bellsouth.net mailbox as the company email, and then plug that address into a newsletter or invoicing tool as the sender, and that breaks. bellsouth.net publishes a DMARC policy of p=quarantine (our lookup, September 19, 2026). Mail that claims to be from bellsouth.net but leaves from some other company's servers fails the check, and receivers are asked to treat it as suspect, which in practice means the spam folder.
You can confirm it in one command: dig TXT _dmarc.bellsouth.net. If a client's open rates collapsed the moment they moved to an email tool, look at the From line before you look at the list. The fix is a domain of their own, which costs about as much per year as a pizza, with SPF and DKIM set up through the tool. No amount of list cleaning repairs mail that fails authentication on the way out.
Questions people ask
Why is bellsouth.net unverifiable?
Because Yahoo runs the mail under AT&T's outsourcing deal, and Yahoo accepts every recipient by policy. There is no protocol answer available to any verifier.
Are BellSouth addresses still delivering?
Many are. AT&T kept the legacy domains working rather than forcing migrations, so the addresses still route.
Should I keep them on a list?
Keep them labeled as unresolved and watch the asynchronous bounces after a send. Treat them as a distinct risk pool rather than folding them into your overall bounce expectation.